Molded key cap for writing machines



March 13, 1951 a. K. GEERLINGS 2,545,026

MOLDED KEY CAP FOR WRITING MACHINES Filed April '7, 1949 INVENTOR GeraldK. 6887252295 1the front w-portion.

'i fian sid i k y ap- Patented Mar. 13, .1951

PATENT OFFICE r e Remin t n n I New A 9: 5,. N a

.norpor i n .of Delaware Application April'l, 1949,Serial*No.-85;993

The present invention relates to key ca p r-- ticularly adapted for useon typewriters and .other writin i machines and particularh to a 1 key.cap molded from suitable la tic material.

The present invention provides .a key can 6 wherein the top andside-portions have round d surfaces merging one into the othertoeliminate a l rp. corners an dtoprovid an up er surface having a concavedepression in the central nort on surroundedon th si and at th r a v arounded ridge portion with the depression open-- ing at .the front ofthe key, the shane being formed to conform with the shape of'the endportion of a person's finger used to engage the pnoerkey surface. Thecao-is-molded to pro- 5 vide front,--side and rear wallportionsextending below the top portion of the key with thefront wall ortionextending about twice as-far''b low rthetop Wall ofthe key as-the-rear'wall. "Thi provldes'for coo ration between theseveralwallpor- 'tions depnding from the top wall to obtain a molded plastic cap havingsubstantial strength with a central partition structuregformedwith -asocket to receive theend ofa keysha-nk-and at-the same time providing acaphavjng a new and pleasin appearance.

According to ;the present invention errors in typing due to overshootingthe key, strikin the key short, orstriki-ng-it to the" left or rightwill be materially-reduced byreason" of the fingerfitting 3G depressionin the top portion of-the key forming a self-centering feature th atwill aid "an operator in properly centering the -fingers on each key ona 'typew-riterkeyboard orthe like. Thearrangement-of the keytop surfacewith rounded corn rs and an open front into 1 the concave depressionwill reduce fatigue in typing due to the finger fittingshape of the keytop as compared w t many n eviou l onnsofkev tops t at do not fit thesha e of-the finger-and have a ridge at In the drawing:

i 1 showsake eo p oonstrnotedra dine to the invention in frontelevation.

Big-2 1s a plan view of --the *key cap.

". li i "i a side v i 'lookine thoilef Fig. *4 'isa verticalcross-section taken on line 4 4 of Fig. 1; i

Fig. 5 is a rear elevation of the key cap.

Fig. 6 is a bottom plan view.

The molded key cap constructed according to the invention is preferablymade of a suitable plastic material molded in one piece. The key cap hasa top wall 1, front wall 2, side walls 3, '55

extending lip-weird and .imorging. into the lochand rear wall 4. Thefront, side, and rear-;yvalls are in d pendin relation from th mar in ftop wall I. Th irear wallhas.a'lenethooua ito about half .of L-the lengh of fron wall :2: do pen in relation ;.-below top avail c h -routersurfa s-of: the =fr nt, .s davand :rea walls where they are Joined tgeth r at 1 the lcorner-S o -.t he key capsarerounded- ;as indicateda-t5 :to provide ;smo th:. ntinuous outer surfaces in -whiohtone wallextending wlat rallyto another isecu ved at the 391 1 2150 mer intothe.latotallyzextending wall :'P -1 0I1.- The bottom edgesof the rear,-siriot and fron walls have -a.-curved formpxtendiI-is fro $11118.reargsu-rface of r-roar :Wall .4 in d o.wnwardly curving and forwardlyext n ng ;:relati n, as indicate at 6 in Fi s. 3 and it, in linin rdwnwardlv toward and to t fr nt surf fifipf fr nt all .2-

transverse entral partiti n .18 formed in d p dingr lationlrrom top wallI and x onds between the central portions of front wall v.2.. and, rearwallod to provide a V rigid. key. cap structure. The central portion ofpartition? is formed with ayertically extendingsocket .8 below top walLlfor sl da ly re eivin theupwardlyex ending end ofa key shankvonga.typeWriter km or other simi- -1arw.rit ng machine key in tight yfitting ifr tiona-l relation.

On pposite si e of central partition 31 ...the bodysof the key-belowtoprwalll ishollow within vfront, side, and rearwalls v2 .3, and .4,respectivel th open compartments between .the .f ont, side. and .rearwalls beineop n. a theh ttomn the k y n.

Top wall Iis formedwith a concavedepression 8 extending throughouttheportions of the top wall .With nthe s de and rear mar n the eof thcurva ur a d si e of the depressi n be n s: a ha to fitt ad n :theend otheaverago .humanfinser. De re si .9 ex ends throu h t .thafrontedg f hk y pwh th 'topwafl is r unded in downwardl extending r l on. so

that the outer surface .willmerge into the front su a e of-ir ntwallz aind oated atJnr nJiig-e- The side and rear margins o .t p wall .l areiormosi .witha ridge l havinaanonve rounded firm with the surfa e ofvconcave... n i= sion1.9

vex surface of ridge II. The convex surface of ridge II extendsoutwardly and curves down wardly to merge into the outer surfaces ofside Walls 3 and rear wall 4 with the corner portions rounded inconformity with rounded corners 5 at the rear corners of the key cap.The formation of ridge I I around the sides and rear of the key and therounded convex surface thereof merges into the concave surface ofdepression 9 to provide a composite shape on top wall i in which thecentral portion of the key with its finger conforming shape and thedepression open at the front of the key fits ones finger so it mayfreely project into the depression in horizontal relation withoutobstruction from the front portion of the key cap.

When a plurality of keys constructed as illustrated in the drawing andabove described, are used on a typewriter keyboard in rows one behindthe other with the keys in each row slightly above the forward row, thelong front wall 2 depending below top wall 1 in a row to the rear andelevated above a preceding row will provide a key cap arrangement wherethe caps on adjacent keys in the row are relatively close together andhave the lower end of the front wall of each key cap extending below thetop wall of the key cap in a preceding row.

The key cap made according to this invention when placed on a pluralityof rows of keys will have the side walls and front and rear walls inadjacent but closely spaced relation to the corresponding walls ofadjacent rows of keys and adjacent key caps in a row, to substantiallyclose the space in the keyboard portion of the machine to an extentsufficient to prevent an operator's fingers from slipping off one keyinto the space between two keys while the shape of the key cap of thepresent invention will also aid in guiding a finger into the centerportion of a key cap where it is not properly aligned therewith.

In using the key cap of the present invention,

an operator in striking a key applies the end pad portion of the fingerto the top of the key cap. In'moving the finger onto the key cap, thepad portion at the lower front end of the finger in horizontal positioncan be moved into the concave depression 9 from the front of the keywithout difiiculty and with a free movement in view of the fact that thefront part of the key top is at the same level as the middle part of thekey top in addition to having the front edge' rounded downwardly andmerging into front wall 2. The ridge portion I i around the sides andrear part of the key helps an operator to properly center the finger onthe key cap by the sense of touch in movement to engage the key cap foroperating a key. The ridge portion H at the rear of the key cap operateseffectively to limit rearward movement of the operators finger on thekey cap to prevent the common fault experienced with previous forms ofkey caps of the operators fingers overshooting the key cap to too greatan extent and thereby interfering with the key caps on keys to the rearof the one which it is desired to operate. This has resulted in breakingfinger nails. With the rounded upper margins and corners on the key capthe finger nails of an operator will not catch on any of the key caps,will be limited by front walls 2 of rearwardly located key caps and willnot slip between adjacent key caps constructed and mounted in a keyboardaccording to the invention. With the side portions of the key capsloping from ridge portion 1 l toward the center an operator will beaided in centering a finger on a key cap with the downward slope at thesides of the key cap tending to cause a finger pad to slide toward thecenter. An operator will not have an impression left in the finger whereit passes over the front end of the key caps made according to thepresent invention in comparison with previous types of keys havingridges across the front. In addition, fatigue in operating a machineequipped with key caps according to the present invention will begreatly reduced and the appearance of the machine will be greatlyenhanced.

The invention claimed is:

1. A key cap for typewriting and similar machines, comprising a moldedbody having integral side, front, top and rear walls, and a centraltransverse wall extending between the front and rear walls, dependingfrom said top wall and formed with a socket for slidably receiving theend of a key-lever, said top wall having a ridge extending along theside and rear edges and having a central valley portion extendingthroughout the central portion of said top wall within said ridge andopen at the front of said cap, said front wall depending substantiallytwice as far as said rear wall below said top wall, said side wallshaving curved lower edges extending from said rear wall to the loweredge of said front wall, said ridge and valley portion of said top wallhaving curved surfaces merging into one another and said top wall havinga downwardly curved surface across the front merging into the frontwall.

2. A key cap for writing machines, comprising a molded body havingimperforate top, side, front and rear walls, said front and rear wallsdepending respectively from the front and rear portions of said top walland said front wall having a depending length approximately twice thatof the rear wall, the side walls, front and rear walls having the loweredge curved downwardly from the rear face of the rear wall in inclinedrelation to the top wall toward and to the front face of the front wall,said rear, side and front walls having rounded outer corner surfaces,said top wall having a concave central depression in the upper facebounded by a convexly rounded ridge along the side and rear portions,said top wall having the upper surface in the central depression merginginto a rounded front surface curving into the front surface of the frontwall, and a central transverse vertical partition integral with thefront and rear walls and depending from the top wall, said partitionhaving a key-shank receiving socket formed therein open at the loweredge.

GERALD K. GEERLINGS.

' REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 726,107 Stanton Apr. 21, 19032,350,787 Martin et a1. June 6, 1944 2,434,886 Henry Oct. 18, 1949

